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Physical Devices |
Microsensors |
Description Sensors can be divided into categories in different ways. One common distinction is between active and passive sensors, i.e., between sensors which send out a signal and react to the response (like radar) and sensors which simply process information about the ambient environment (like thermometers). Another way to sub-divide sensors is into imaging, i.e., those that produce a "picture" of the physical object they sense, and non-imaging, which do not. |
Special Characteristics As an example of imaging sensors, charge-coupled devices (CCD) are used in cameras to give high-resolution images limited by the number of pixels used. Sensor arrays containing millions of pixels, each a few microns across, are possible. As pixel size has shrunk and data available to the system has grown, processing has gained importance. Because of their particular importance, imaging, non-imaging, and passive sensors are singled out in this discussion. Impact on Economy A variety of civilian and military applications are dependent on imaging sensors. Imaging sensors are also critical in remote sensing from space, scanning microscopy, and machine vision (an important area of robotics). Imaging sensors contribute to a number of national goals, including healthy and educated citizenry, job creation and economic growth, harnessing information technology, improved environmental quality, and enhanced national security. Impact on Security Passive sensors have a special importance in military applications because they do not reveal their location or characteristics to an adversary. There are several important applications that can be emphasized for passive sensors. For example, they can provide warning of an adversary's active sensors, enhance night vision, or be used for thermal imaging to identify and target military assets and then perform damage assessment. Radar guided missiles, laser designation systems, and laser range finders are a few examples of offensive systems that detectors could search for, and upon detection alert friendly forces to imminent threats. Damage assessment is a vital task to follow-up strikes, and with the advent of new weapon types remains particularly critical. Worldview Europe and Japan have lost their leads in chemical and biosensor technologies over the last several years, although the Japanese are involved in a very broad range of biosensor development for both biomedical and bioprocess control applications. U.S. firms have stepped up R&D efforts as a result of environmental monitoring needs, a rekindled interest in developing better chemical and biological defense detection capability, and the marketing success of some biosensor-based medical diagnostic kits, e.g., "consumer- friendly" home pregnancy and blood sugar tests. What's the use? Although imaging sensors are very important in providing "visual" information, a collection of non-imaging sensors can be used to measure a vast range of phenomenology. Examples include devices that measure temperature, pressure, humidity, radiation, voltage, current, or presence of a particular chemical or biological material. In addition to passive sensors, there are active sensors such as laser or radar altimeters. Specialized microsensors can be used to detect particular chemical or biological agents. Non-imaging sensors are used in a variety of industries and applications. Environmental monitoring and hazardous site characterization are important applications for non-imaging sensors, including biosensors and chemical sensors. Miniaturization of biosensors is important to medical diagnostics, food process control quality assurance. Small and inexpensive if produced in large volumes, biosensors can detect small changes permitting earlier treatment with smaller doses of medication. Chronically implanted devices employing a microbiosensor can be therapeutic as well as diagnostic. For example, a smart device employing a microbiosensor could respond to changes in metabolic rates and circulating biochemicals, and adapting to the patients present physiological status, automatically release the proper dosage of a therapeutic medication. The transportation industries are finding uses for microsensors and MEMS. Microsensors have use in the automotive industry for system controls and diagnostics. Non-imaging sensors have a role in remote sensing. Laser profilers (LIDARs) and radar altimeters can be used to measure range, and hence altitude giving surface. These can be used as navigation aids, and are related to imaging systems to the extent that surface profiles are being probed. Soil-sounding radars are an important recent development. Robotics is an important area for non-imaging sensors. Tactile sensors are often considered second in importance only to machine vision. Sensors are also important for balance and kinematics. Military applications of biosensors, chemical sensors, and microsensor variants include detection and warning of the use of chemical or biological agents in warfare. Given the wide range of applications to which non-imaging sensor technologies contribute, they can be said to contribute to meeting almost all of the President's goals. |